Paving the way for tailor-made treatments to stop smoking, researchers have shown that finding out how quickly smokers break down nicotine in their bodies is the key to helping them quit.
"Our findings show that matching a treatment based on the rate at which smokers metabolise (break down) nicotine could be a viable clinical strategy to help individual smokers choose the cessation method that will work best for them," said co-lead author Caryn Lerman, professor of psychiatry at the University of Pennsylvania in the US.
A simple blood test could point out how fast smokers break down nicotine, the researchers said.
Smokers crave nicotine when their body's nicotine levels drop. However, different people metabolise nicotine at different rates.
Nicotine levels in the body drop more quickly in normal metabolisers (60 percent of smokers in the population) so they are more likely to smoke more and find it harder to quit.
The researchers compared the efficacy of a non-nicotine based drug called varenicline with that of a nicotine patch.
They found that normal metabolisers of nicotine have better quit rates with the non-nicotine replacement therapy drug varenicline.
Although varenicline was just as effective as nicotine patches at helping slow metabolisers to quit, the former reported more overall side-effects with the drug.
The study involved 1,246 smokers who wanted to quit.
"Our data suggests treating normal metabolisers with varenicline and slow metabolisers with the nicotine patch," co-lead author Rachel Tyndale, from the University of Toronto, in Canada, added.
"What is more, it is feasible that a point-of-care blood test to measure the rate at which nicotine is metabolised could be developed and implemented in clinical practice," Tyndale said.
The study was published in The Lancet Respiratory Medicine journal.